Methods for page and location on queried content

2 files changed, 32 insertions, 4 deletions

diff --git a/src/model/content.rs b/src/model/content.rs
index 5317236e..3c661929 100644
--- a/src/model/content.rs
+++ b/src/model/content.rs
@@ -2,6 +2,7 @@ use std::any::TypeId;
 use std::fmt::{self, Debug, Formatter, Write};
 use std::hash::{Hash, Hasher};
 use std::iter::{self, Sum};
+use std::num::NonZeroUsize;
 use std::ops::{Add, AddAssign, Deref};
 
 use ecow::{eco_format, EcoString, EcoVec};
@@ -9,10 +10,10 @@ use once_cell::sync::Lazy;
 
 use super::{
     node, Behave, Behaviour, Fold, Guard, Locatable, Recipe, StableId, Style, StyleMap,
-    Synthesize,
+    Synthesize, Vt,
 };
 use crate::diag::{SourceResult, StrResult};
-use crate::doc::Meta;
+use crate::doc::{Location, Meta};
 use crate::eval::{
     cast_from_value, cast_to_value, Args, Cast, Func, FuncInfo, Str, Value, Vm,
 };
@@ -185,6 +186,22 @@ impl Content {
         self.field(field).ok_or_else(|| missing_field(field))
     }
 
+    /// Determine the page of this content.
+    pub fn page(&self, vt: &Vt) -> StrResult<NonZeroUsize> {
+        match self.stable_id() {
+            Some(id) => Ok(vt.introspector.page(id)),
+            None => Err("this method can only be called on queried content".into()),
+        }
+    }
+
+    /// Determine the location of this content.
+    pub fn location(&self, vt: &Vt) -> StrResult<Location> {
+        match self.stable_id() {
+            Some(id) => Ok(vt.introspector.location(id)),
+            None => Err("this method can only be called on queried content".into()),
+        }
+    }
+
     /// The content's label.
     pub fn label(&self) -> Option<&Label> {
         match self.field("label")? {
diff --git a/src/model/typeset.rs b/src/model/typeset.rs
index 683f2846..162a2a67 100644
--- a/src/model/typeset.rs
+++ b/src/model/typeset.rs
@@ -53,8 +53,7 @@ pub fn typeset(
 
 /// A virtual typesetter.
 ///
-/// Holds the state needed to [typeset] content. This is the equivalent to the
-/// [Vm](crate::eval::Vm) for typesetting.
+/// Holds the state needed to [typeset] content.
 pub struct Vt<'a> {
     /// The compilation environment.
     pub world: Tracked<'a, dyn World>,
@@ -66,6 +65,18 @@ pub struct Vt<'a> {
     pub introspector: Tracked<'a, Introspector>,
 }
 
+impl Vt<'_> {
+    /// Mutably reborrow with a shorter lifetime.
+    pub fn reborrow_mut(&mut self) -> Vt<'_> {
+        Vt {
+            world: self.world,
+            tracer: TrackedMut::reborrow_mut(&mut self.tracer),
+            provider: TrackedMut::reborrow_mut(&mut self.provider),
+            introspector: self.introspector,
+        }
+    }
+}
+
 /// Provides stable identities to nodes.
 #[derive(Clone)]
 pub struct StabilityProvider {